It did taht and we always have to set the clutch is slipping (wire+screw)
Huh?
With all woodruff keys in place the motor sprocket, clutch shaft and (gear side) clutch base should be one rigid unit, meaning they all turn together. The pressure plate will also rotate with this unit due to the three studs that poke through the holes on the pressure plate. The large (internal) spring around the clutch shaft pulls inward on the rod that the flower nut is attached to, this pulls the pressure plate inward squeezing the clutch pads between the clutch base and pressure plate.
Check out this excellent thread posted by Norman showing the clutch shaft taken apart to get a better grip on what is happening there... (pun intended)
http://motorbicycling.com/showthread.php?t=8392
...with all woodruff keys in place the motor sprocket, clutch shaft, clutch plate and pressure plate should all rotate together as one unit, the large bevel gear will only rotate when the pressure plate is squeezing the clutch pads.
You adjust the pressure exerted on the pads by turning the flower nut. Pull in and lock the handlebar clutch lever, you should see the pressure plate move outward and release pressure on the pads. Remove the screw that locks the flower nut and then tighten the flower nut to increase the grip of the clutch, loosen flower nut to reduce the grip. (When the clutch lever is locked in the flower nut should turn easily) It's a pretty simple task to adjust the flower nut so the pressure plates squeeze the pads tightly when released, and loosens completely when you lock in the handlebar clutch lever in....